5.2.4 The Alt modifier and editor bindings

In MS Windows emulation on MS Windows, keystrokes with the
Alt
modifier key are used by the system to activate the menu bar. Therefore these keystrokes, for example
Alt+A
and
Alt+Ctrl+A
are not available to the editor.

Windows accelerators always take precedence over editor key bindings, so in Emacs emulation the
Alt
modifier key only acts as Meta though keystrokes with
Alt
if there is no accelerator which matches.

On Cocoa, the preference for the Meta key affects the operation of menu accelerators (shortcuts). If
Command
is used as Meta, then it will not be available for use as an acclerator.